Unit 1.2 Flashcards
What does RAM stand for?
Random Access Memory
What is the purpose of RAM?
It holds programs and data that is currently in use on the computer – which includes the operating system. The CPU (a separate piece of hardware) reads the instructions and data from RAM. The more RAM you have the more programs you can open at once.
What are the features of RAM?
- It is volatile (loses data when power is off)
- it is read / write
What does ROM stand for?
Read Only Memory
What is the purpose of ROM?
This type of memory stores the information needed to boot up the computer (the bootstrap loader). It contains the BIOS (Basic Input Output System) that lets you use a keyboard, mouse and displays things to the screen.
What are the features of ROM?
- It is non-volatile (keeps data when power is off)
- it is read only (although technically there are ways to write to ROM – look-up PROM, EPROM, EEPROM)
What is virtual memory?
If you have a lot of applications open RAM can start to get full as all open programs and data are stored here. To prevent the computer from crashing due to a lack of ‘memory’ it uses ‘virtual memory’ when RAM gets overloaded. This is an area on the hard drive that is used as a temporary storage space, as if it were RAM.
What programs and data are put into virtual memory when RAM is full?
The least recently used programs can be swapped out of real RAM into virtual memory to make room for a new program in RAM.
What are the advantages of virtual memory?
- You can run more applications at once.
- You can run larger applications with less real RAM.
- You don’t have buy more memory RAM
What are the disadvantages of virtual memory?
- Applications run slower (because transferring from the hard drive is slower than from RAM).
- It takes more time to switch between applications.
- Constant use of virtual memory results in ‘disk thrashing’
- Less hard drive space for your use
Define disc thrashing:
The process of constantly accessing data from the hard drive.
What is flash memory?
A type of re writable, non-volatile memory that is used in countless modern storage situations
What are examples of flash memory?
USB pen drives
SD cards
Internal storage on phones and mp3 players
Solid state drives
What does DRAM stand for?
Dynamic RAM
What is DRAM?
Dynamic RAM is a type of memory that requires the data to be refreshed every so often so that data isn’t lost (through capacitor leakage) – it is less expensive than SRAM.
